This phase II, randomized, multicenter, double-blind study will compare the effects of delavridine mesylate (DLV), combined with zidovudine (ZDV or AZT) or didanosine (ddI), or both ZDV and ddI, to ZDV plus ddI alone, in HIV-infected patients. The study will determine if DLV combined with ZDV and/or ddI improves the benefits of these drugs in HIV disease. (ACTG 261)